Traditionally EEG electrodes are placed equidistant from each other and cover all of the area of the head. This provides a map or image of the brain wave energy over the surface area of the brain. More advanced EEGs (e.g., available from EmSense Corporation, San Francisco, Calif.) that are targeted at specific measurements are designed with a single electrode at a specific position to produce a specific state or response. The limitation of this methodology is that there is some variation in brain position and structure and the optimum position for the measurement cannot be determined for each individual without extensive experimentation.